Coloproctology Unit, Department of General Surgery, Hospital Dr. Domingo Luciani, Venezuela. Department of Colorectal Surgery, General Surgery Division, Royal Hospital, Oman. Department of General Surgery, Mother Hospital, Kerala, India. Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea. Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea. Electronic address: namkyuk@yonsei.ac.